On most motor graders and other types of construction machinery which have a plurality of hydraulic control levers for activating various functions of the machine, the control levers remain in the same neutral position when not in use. As so often happens, particularly during the operation of a motor grader in doing rough roadwork, the operator can run the machine in a seated position so that it is desirable to have the control levers in a lowered neutral position. On the other hand, when the operator is doing fine roadwork such as forming a ditch bed along the roadside, the operator usually prefers to operate the control levers in a standing position so that all of the functions of the machine can be observed and slight changes in the blade height and angle may be quickly made. In such an instance it is desirable to have the control levers in a more upright neutral position. However, most motor graders at present do not provide for an apparatus which can vary the neutral position of the control levers to facilitate standing and seated operation of the machine.
The apparatus according to this invention overcomes the above problem by providing means to adjust the neutral position of the control levers between upright to any desired tilted position to facilitate standing or seated operation of a machine. The apparatus also permits positioning of the control levers in the upright position to facilitate entry to and exit from the operator's cab. The apparatus comprises a bearing having a longitudinal axis, means for eccentrically mounting the bearing about a central axis which is spaced apart from and parallel to the longitudinal axis of the bearing, the means for mounting the bearing permitting the bearing to revolve or orbit about the central axis and means for selectively retaining the bearing in a plurality of desired radial positions relative to the central axis so as to provide a plurality of different neutral positions for the control lever. The relationship of the essential elements of the invention is that an end of a control lever is secured to the bearing to permit the control lever to pivot about the longitudinal axis of a shaft it is mounted on. A connecting rod has a first end pivotally connected to the control lever, and a second end connected to a device which is to be activated by the control lever. The first end of the connecting rod pivots about an axis which is coincident with the central axis of the apparatus. When it is desired to activate the device with the control lever, the control lever is pivoted about the longitudinal axis of the shaft to move the connecting rod. However, when it is desired to change the neutral position of the control lever, the control lever pivots about the central axis as the bearing is revolved about the central axis to change the radial position of the control lever relative to the central axis. During this changing of the neutral position of the control lever the connecting rod may remain stationary. The means for retaining the bearing in the desired radial position is used when the new neutral position of the control lever is attained.
As mentioned hereinabove, the apparatus may be part of the hydraulic control console of a motor grader and the like where the plurality of control levers of the console may be positioned in a number of different neutral positions in unison.
The means for eccentrically mounting the bearing may comprise one or more arms, a first end of each arm being connected to an end of the shaft on which the bearing is mounted and a second end of each arm being rotatively mounted about the central axis of the apparatus. The means for selectively retaining the bearing of the apparatus in a plurality of desired radial positions may be integral with one of the arms and include a quadrant-shaped body portion which is attached to the bearing. It may have an apex which is mounted adjacent the central axis and a diametrically opposed arced surface wherein a plurality of circumferentially spaced-apart notches are located. A spring-loaded arm may be used which is pivoted about an axis and permits the arm to engage any one of the notches to retain the bearing of the apparatus in the desired radial position thereby retaining the control lever in the desired neutral position.